Twitter and Facebook have taken down numerous accounts they say are tied to a Chinese state-run disinformation campaign to undermine the Hong Kong protests.

On Monday, Facebook announced it had removed several pages, groups and accounts "involved in coordinated inauthentic behavior as part of a small network that originated in China and focused on Hong Kong." It said the people involved "engaged in a number of deceptive tactics," including using fake accounts "to manage Pages posing as news organizations, post in Groups ... and also drive people to off-platform news sites." Facebook said it "conducted an internal investigation" after receiving a tip from Twitter.

Both platforms shared examples of the posts made by these entities. One compares protesters to ISIS soldiers, with the caption: "Protesters. ISIS fighters. What's the difference?" Another post simply says, "cockroach soldiers," with an image of protesters' faces photoshopped onto the bodies of cockroaches.

The companies' actions follow a massive march in Hong Kong on Sunday. Organizers said as many as 1.7 million people turned out for the protest, making it the second-largest march of the movement so far. Hong Kong's government noted that the protest remained peaceful but reiterated that officials will begin working with protesters after the demonstrations have stopped.